For exam purposes deduction for expenses on which TDS is deductible is allowable if the expenses relate to period from April to Feb then TDS to be dedposited upto 31st March and if expenses relate to March then TDS can be deposited upto the date of filing return. If not paid within the time limits prescribed then expenses disallowable u/s 40(a)(ia).
So in the above case
1.)EXPENSE CREDITED ON 15/03/2009 AND DEPOSITED TDS ON 02/06/2010
Expenses will be allowable in F. Y. 2010 - 11.
If expenses credited on 15.03.2010 (instead of 15.03.2009) then expenses allowable in F. Y. 2009 - 10 itself as TDS deposited before due date of filing return.
2.) EXPENSE CREDITED ON 31/03/2009 AND TDS PAID ON 02/04/2011
Expenses will be allowable in F. Y. 2011 - 12.
If expenses credited on 31.03.2010 (instead of 31.03.2010) then also expenses allowable in F. Y. 2011 - 12.